Both of mine love their bags and love going out with Mommy. I started Jewelina young but Jaden wasn't in a bag until he was almost a year old!

Make it a fun thing for them, put a toy in there or a pixie stick. Just put them in the bag and keep it open and pet them inside the bag on your lap. Then enventually, put it on your shoulder zipped and walk around the house for a while, say 10 minutes or so. Increase the time a little longer. Then move outside, go walk around the block, go talk to someone carrying him in the bag. Get him used to all those noises and people. The more you put him in there, the more he'll learn to like it. Both of mine do wonderful in bags, I put them in and they lay down and enjoy the ride. In fact, my boy often just goes to sleep in there while we are out running errands
Good luck to you and PM me if you have any questions!